Power-factor corrected transformer



March 28, 1950 w. 'FOERSTE 2,502,084

POWER-moron CORRECTED TRANSFORMEI Origihal Filed Sept. 26, 1941 INVENTOR. mLL/A M FoERs TE A T TOR/V5 Y Pmsea Mar. 28, 1950 POWERFACTOB CORRECTED TRANSFORMER William Foerste, Pelham Manor, N. Y.; Anna Kane, administratrix of said William Foerste, deceased, assignor of one-half to Eugene A.

Quarrie, Scarsdale, N. Y.

Original application September 26, 1941, Serial No. 412,492. Divided and this application July 30, 1945, Serial No. 607,748

5 Claims. (Cl. 323-61) The invention relates to high reactance, magnetic leakage transformers suited, for example, to the operation of rectifiers such as the gasfllled or oxide types, variable speed motors, gasfilled lamps of the ordinary luminescent or fluorescent types, etc. cially with a transformer of this nature which is suitably corrected as to power factor, as is set forth in my copending application Serial No. 412,492, filed September 26, 1941, which has matured into U. S. Letters Patent No. 2,392,845, dated January 15, 1946, and of which this application is a division.

It has for an object to provide means in connection with the novel transformer arrangement of said pending application for correcting the power factor.

A further object is to provide at the same time means which will preserve the control contacts, employed for varying the output of the novel transformer, against welding, pitting and general deterioration.

In carrying out the invention, a transformer having a closed magnetic core, only one primary and at least one secondary, is provided with a high reluctance variable reactor in single-acting shunt magnetic relationship and separated from the core by a non-magnetic gap, and said reactor is provided with a coil connected with the said primary through a condenser also connected with the source of energy supply.

The nature of the invention, however, will best be understood when described in connection with the accompanying drawing which illustrates the novel transformer control arrangement associated with power factor correcting means.

Referring to the drawing, designates the closed core structure of a transformer of the type set forth in my copending application, Serial No. 412,492, filed September 26, 1941; and said core may be constructed in the usual manner of laminated iron and affords a closed magnetic circuit. A primary winding l I is provided thereon and derives its power from the main 12 through a lead 13 and a switch-arm it connected with a lead IS. A secondary winding 15 is also provided on the core for supplying power at a substantially constant open circuit voltage to a load of relatively low operating voltage, for example, loads such as are encountered in the operation of gas-filled lamps a the ordinary luminescent type or of the fluorescent type. Thus the said secondary winding is shown as connected directly to the electrodes 16 and I1, either of the It is concerned more espea transparent envelope l8. Winding i5 is in inductive relationship to the primary, being coupled as closely as possible therewith, and supplies the lamp with the requisite voltage for its proper operation.

In the operation of these lamps, it is understood that an imtially high voltage must be supplied by the secondary to effect ionization of the rare gas in the envelope, this voltage then dropping to a much lower sustaining or working value when the lamp is in service. The novel arrangement hereinaiter set forth, also, aifords at the same time a ballast to prevent overheating of the tube and disintegration of the tube elements, thereby maintaining the current density and the light intensity.

In accordance with the invention, an auxiliary core '20 extends within the main core structure to afford a high leakage reactance element or hot or cold type, of a luminescent lamp including magnetic shunt separated from the core by a nonmagnetic gap, said auxiliary core 20 serving to shunt from the secondary [5 a portion of the flux generated by the said primary II. There is provided over said core a coil or control winding for the primary load, and, the winding is divided, for example, into two coil portions 2| and 22, as by means of a tap 23. A lead 24 from one end of the divided winding permanently connects the latter to one end of the primary winding H, the other end of said divided winding being connected by means of a lead 25 to a switch contact point 26. The other end of primary winding ll connects directly with the power main I2 through the lead l3. Tap 23 is connected to one electrode of a condenser 21, the other electrode of which is connected through a lead 28 with the power lead I3 through one end of an auxiliary winding 29 provided on the core and having its other end connected with the primary at the latters junction with the lead [3 to constitute with said primary an auto-transformer.

Condenser 21 thus remains permanently connected in series with the primary and with a portion of the inductance provided by the divided control winding. The latter as a whole may be introduced in serie with the primary winding II by means of switch-arm l4 when said arm is moved to contact the switch-point 26, said arm also being connected with the other lead 13 of the power main I2. When the switch-arm is on the contact point 30 connected with one end of the primary winding, said winding only is in circuit, except for the connection through the condenser 21.

By thus bridging a condenser across the primary winding II and associated auxiliary core winding 28, power factor correction is readily attained. Also, by this expedient, the winding, in providing an increased voltage, allows of the use of a smaller capacity condenser. Moreover, the winding portions may be in the nature of inductance buil'er coils to check momentarily the surge of condenser discharges on closing of the circuit through the switch-arm M to the switchpoints 26 and 30, thereby obviating welding of the arm to a point.

I claim:

1. A power-factor-corrected transformer having a closed magnetic core, only one primary winding adapted for connection to power leads, and at least one secondary winding; a high reluctance variable reactor in single-acting shunt magnetic relationship with said core, magnetically positioned between the said primary and secondary windings and separated from the core by a non-magnetic gap for shunting from said secondary winding a portion of the flux generated by said primary winding, said reactor including a winding in series with the primary winding; and a condenser connected with the reactor Winding and the primary winding in parallel relationship.

2. The transformer of claim 1, wherein said reactor includes a coil for controlling the load of said single primary winding and one end thereof is permanently connected thereto, a tap is provided on said coil, and means are provided for connecting the tap to said primary winding.

3. The transformer of claim 1, wherein said reactor includes a coil for controlling the load 01' said single primary winding and one end thereof is permanently connected thereto, and means are provided to connect alternatively said single primary winding to a source of electrical energy or in series with the reactor coil to said source.

4. The transformer of claim 1, wherein said reactor includes a coil for controlling the load of said single primary winding and one end thereof is permanently connected thereto, and an auxiliary winding is provided on the core having one end connected with the other end of said single primary winding to constitute therewith an auto-transformer, the other end of said auxiliary winding being connected with the reactor coil, and the condenser is included in series in the connection.

5. The transformer of claim 1, wherein said reactor includes a coil for controlling the load of said single primary winding and one end thereof is permanently'connected thereto and to a contact point, and an auxiliary winding is provided on the core having one and connected with the other end of said single primary winding to constitute therewith an auto-transformer, the other end of said auxiliary winding being connected with the reactor coil, the condenser being included in series in the connection, a tap is provided on said coil and is connected to a second contact point, and a switch-arm connected to one of the power leads is adapted for alternative engagement with the said contact points.

WILLIAM FOERSTE.

REFERENCES CITED The following references are of record in the file of this patent:.

UNITED STATES PATENTS Number Name Date 1,599,570 Lucas Sept. 14, 1926 1,599,579 Lucas Sept. 14, 1926 1,950,395 Boucher Mar. 13, 1934 2,179,795 McCurtaln Nov. 14, 1939 2,297,674 Stevens Sept. 29, 1942 2,312,768 Mitchell Mar. 2, 1943 2,352,073 Boucher June 20, 1944 

